城市园林绿地土壤CO_2排放通量的研究

Research of CO_2 Fluxes from Urban Garden Soils

采用静态箱—红外分析仪法测定了西南大学8块典型园林绿地的土壤CO2排放通量,8块研究点的植被分别为:结缕草(G1)、金叶女贞(G2)、结缕草(G3)、结缕草(G4)、麦冬(G5)、结缕草(G6)、三叶草(G7)、竹林(G8).结果表明:G1-G8的土壤CO2排放通量均呈明显的季节变化,夏季最大,春秋季次之,冬季最小;在累积监测355d的时间内,G6的累积排放量最高,为11 116kg/hm2,G2的累积排放量最低,为3 853kg/hm2;G3,G7和G8的CO2排放通量与土壤含水率呈显著相关(p【0.05),而其他绿地中则无明显关系;CO2排放通量与5cm土温(T5)的相关性均达到极显著水平(p【0.01),可解释CO2排放通量变化的70.0%~86.2%,G1-G8的温度敏感性(Q10)在1.94~2.53之间;生长年限对CO2排放量的大小影响不显著.

The static closed-chamber method and an infra-red analyzer were used to determine CO2fluxes from typical garden soils at eight sites within the campus of Southwest University.The vegetations of the sites were Zoysia(G1),California Privet(G2),Zoysia(G3),Zoysia(G4),Ophiopogon(G5),Zoysia(6),Clover(7)and Bamboo(G8).CO2fluxes of G1-G8all showed a significant seasonal variation,with the maximum in summer,the minimum in winter,and spring and autumn in between.During the 355 days of monitoring,the cumulative emission was the greatest(11 116kg/ha)in G6and the least(3 853 kg/ha)in G2.CO2flux was correlated significantly(p<0.05)with soil moisture in G3,G7and G8and non-significantly at the other sites.Regression analysis showed that the relationship between CO2fluxes and soil temperature of 5cm depth(T5)could be described with an exponential equation with high significance(p<0.01),which could explain 70.0%-86.2% of CO2fluxes change.Temperature sensitivity(Q10)of G1-G8varied between 1.94and 2.53.Effect of the age of the green spaces on the magnitude of CO2fluxes was non-significant statistically.